T8775A,C THE DIGITAL ROUND™
Wiring
IMPORTANT
Use 18-gauge wire to wire the T8775A,C Thermostats.
All wiring must comply with local electrical codes and ordinances. Disconnect the power supply to prevent electrical shock or equipment damage.
Refer to Fig. 2 through 6 for typical wiring hookups.
| R |
| W |
1 | HEATING |
RELAY OR | |
| VALVE COIL |
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
M19513
Fig. 2. Typical hookup of T8775A in a heat-only system.
| O | |
| B | |
2 | Rc | |
| G | |
R | Y | |
W | ||
|
1 | HEATING | FAN |
RELAY OR | ||
| VALVE COIL | RELAY |
|
|
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
2 FACTORY INSTALLED JUMPER. | M19514 |
Fig. 3. Typical hookup of T8775C in heat-only system
with fan.
| 2 |
| O | |
| B | |
2 | Rc | |
| G | |
R | Y | |
W | ||
|
1 | HEATING | COMPRESSOR | FAN |
| RELAY OR | CONTACTOR | RELAY |
| VALVE COIL |
|
|
| 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS | ||
| AND OVERLOAD PROTECTION AS REQUIRED. | ||
2 FACTORY INSTALLED JUMPER. | M19515 |
Fig. 4. Typical hookup of T8775C in heat-cool system
with single transformer.
Rc | B | |
G | ||
2 | ||
Y | ||
R | ||
W | ||
|
|
| COMPRESSOR |
|
|
| CONTACTOR |
|
| HEATING | FAN |
|
1 | RELAY OR | RELAY | 1 |
| VALVE COIL |
|
|
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
2REMOVE FACTORY INSTALLED JUMPER BETWEEN R AND RC.
M19517
Fig. 5. Typical hookup of T8775C in heat-cool system
with two transformers.
| 4 |
|
| O |
|
| B |
|
| Rc |
|
2 | G |
|
Y 3 |
| |
R |
| |
| W |
|
| COMPRESSOR | HEAT |
| CHANGEOVER | |
| CONTACTOR | |
| VALVE | |
|
|
1 | FAN | COOL |
| RELAY | CHANGEOVER |
| VALVE | |
|
| |
1 | POWER SUPPLY. PROVIDE DISCONNECT MEANS | |
| AND OVERLOAD PROTECTION AS REQUIRED. | |
2 | FACTORY INSTALLED JUMPER. |
|
3 | USE A JUMPER WIRE (NOT SUPPLIED) TO CONNECT W TO Y. | |
4 | USE EITHER O OR B FOR HEAT PUMP CHANGEOVER. | |
|
| M19516 |